U.S. patent number 6,304,448 [Application Number 09/657,236] was granted by the patent office on 2001-10-16 for power module.
This patent grant is currently assigned to Mitsubishi Denki Kabushiki Kaisha. Invention is credited to Masakazu Fukada, Dai Nakajima, Ken Takanashi.
United States Patent |
6,304,448 |
Fukada , et al. |
October 16, 2001 |
Power module
Abstract
Obtained is a power module which is excellent in electromagnetic
shielding effects, is rarely influenced by external noises and acts
as an external noise source with difficulty. An insulating
substrate (5) is bonded through a solder (4) to a top surface of a
heat sink (3) fixed to a support plate (2). A DC capacitor (16) is
fixed to a bottom face of the heat sink (3) by adhesion. A control
substrate (11) having a control IC (13) mounted thereon is fixed to
the support plate (2). Moreover, a plurality of electrodes (10), a
DC side electrode and refrigerant inlet-outlet (9) and a control
connector (15) are provided on the support plate (2). A case (1) is
fixed to a peripheral portion of the support plate (2), and
surrounds the insulating substrate (5), the control substrate (11),
the heat sink (3) and the DC capacitor 16 together with the support
plate (2). Both the case (1) and the support plate (2) have
conducting property.
Inventors: |
Fukada; Masakazu (Tokyo,
JP), Nakajima; Dai (Tokyo, JP), Takanashi;
Ken (Tokyo, JP) |
Assignee: |
Mitsubishi Denki Kabushiki
Kaisha (Tokyo, JP)
|
Family
ID: |
18579240 |
Appl.
No.: |
09/657,236 |
Filed: |
September 7, 2000 |
Foreign Application Priority Data
|
|
|
|
|
Mar 3, 2000 [JP] |
|
|
12-058676 |
|
Current U.S.
Class: |
361/700;
174/16.3; 257/692; 257/718; 257/723; 307/10.1; 361/702; 361/705;
361/719; 361/806 |
Current CPC
Class: |
H05K
7/209 (20130101); H05K 1/144 (20130101); H01L
2224/32225 (20130101); H01L 2224/48227 (20130101); H01L
2224/73265 (20130101); H01L 2924/19107 (20130101); H01L
2224/73265 (20130101); H01L 2224/32225 (20130101); H01L
2224/48227 (20130101); H01L 2924/00012 (20130101); H01L
2224/49109 (20130101); H01L 2924/3025 (20130101); H01L
2924/30107 (20130101); H01L 2924/3025 (20130101); H01L
2924/00 (20130101); H01L 2924/30107 (20130101); H01L
2924/00 (20130101); H01L 2224/32225 (20130101); H01L
2224/73265 (20130101); H01L 2224/49109 (20130101); H01L
2924/00 (20130101); H01L 24/73 (20130101) |
Current International
Class: |
H05K
7/14 (20060101); H05K 7/20 (20060101); H05K
1/14 (20060101); H01K 007/20 () |
Field of
Search: |
;361/600,679,686,687,689,701-712,714-723,816,735-738,750-752,683,753
;257/696,706,713,723,724,796,728,762,764,770
;174/16.3,52.1,52.2,50.51,50.52,35MS,50.54,58,35R
;165/80.3,80.6,185,104.21,104.33,104.34
;251/712-718,706-708,746,747,668,684,796 ;428/64,65,195,522
;29/390.03,521,505,557 ;318/139,494,504,432-434 ;364/424.01
;307/9.1,101,147,58,45,82 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Tolin; Gerald
Assistant Examiner: Datskovsky; Michael
Attorney, Agent or Firm: Oblon, Spivak, McClelland, Maier
& Neustadt, P.C.
Claims
What is claimed is:
1. A power module comprising:
an insulating substrate having a main surface on which a power
semiconductor device is mounted;
a control substrate on which a control IC for controlling said
power semiconductor device is mounted;
a conductive support plate to which said insulating substrate and
said control substrate are directly fixed; and
a conductive case fixed to a peripheral portion of said support
plate for surrounding said insulating substrate and said control
substrate together with said support plate.
2. The power module according to claim 1, further comprising a heat
sink provided in said case and kept in contact with a back face of
said insulating substrate which is opposite to said main
surface,
said support plate including:
a refrigerant inlet-outlet coupled to said heat sink;
an electrode electrically connected to said power semiconductor
device; and
a control connector electrically connected to said control IC,
all of them being provided through said support plate.
3. The power module according to claim 2, wherein said power
semiconductor device is a voltage-source inverter,
said power module further comprising a DC capacitor provided in
contact with said heat sink opposite to said insulating substrate
in said case.
4. The power module according to claim 3, wherein said DC capacitor
has P and N electrodes making a pair, and
said refrigerant inlet-outlet is connected as a DC side electrode
and refrigerant inlet-outlet to said P and N electrodes.
5. The power module according to claim 2, wherein said refrigerant
inlet-outlet, said electrode and said control connector are bonded
to said support plate with a room temperature setting adhesive.
6. The power module according to claim 1, further comprising a
shield plate provided between said insulating substrate and said
control substrate in said case.
7. The power module according to claim 1, wherein said case and
said support plate are bonded to each other with sealing property
kept therein.
8. The power module according to claim 7, wherein said case and
said support plate are bonded to each other by seam welding.
9. The power module according to claim 7, wherein said case and
said support plate are bonded to each other by adhesion.
10. The power module according to claim 9, wherein said case and
said support plate are bonded with a conductive adhesive.
11. The power module according to claim 7, wherein an internal
space constituted by said case and said support plate is filled
with an inactive material having insulating property.
12. The power module according to claim 11, wherein said material
functions as a refrigerant,
said power module further comprising a fan provided in said case
for circulating said material in said case.
13. The power module according to claim 1, wherein said case is
constituted by a laminated film in which a plastic thin film is
formed on a metal foil.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a structure of a power module, and
more particularly to a structure of a power module comprising an
insulating substrate having a power semiconductor device mounted
thereon and a control substrate on which a control IC for
controlling the power semiconductor device is mounted.
2. Description of the Background Art
FIGS. 5 and 6 are perspective and sectional views showing a
structure of a conventional power module. As shown in FIG. 6, the
conventional power module comprises an insulating substrate 105 and
a control substrate 113 on which circuit patterns (not shown) are
formed respectively, interconnection leads 110 and 120, and an
insulating case 107. A power semiconductor device 109 is mounted on
the insulating substrate 105 through a solder 108. The insulating
substrate 105 is provided in contact with a metallic base plate 102
through a solder 104.
A control IC 115 for controlling the power semiconductor device 109
is mounted on the control substrate 113 through a solder 114. One
of ends of the interconnection lead 110 is electrically connected
to the insulating substrate 105 or the power semiconductor device
109 through a metal wire 111. The other end of the interconnection
lead 110 is electrically connected to an electrode 122 provided on
the control substrate 113. The electrode 122 is electrically
connected to the control IC 115. One of ends of the interconnection
lead 120 is electrically connected to the power semiconductor
device 109 through a metal wire 121. The other end of the
interconnection lead 120 is electrically connected to an electrode
123 provided on the insulating case 107.
The insulating substrate 105, the control substrate 113 and the
interconnection leads 110 and 120 are provided in the insulating
case 107. An internal space of the insulating case 107 provided
below the control substrate 113 is filled with a silicone gel 112.
Moreover, a cover 117 is fixed to a top of the insulating case 107.
The control IC 115 is electrically connected to a control connector
119 provided on the cover 117 through an external connecting
terminal 118 soldered onto the control substrate 113.
The base plate 102 is fixed to a heat sink 101 with a bolt 103. A
thermal conduction grease 116 is coated comparatively thickly
(approximately several hundreds .mu.ms) between the base plate 102
and the heat sink 101.
According to such a conventional power module, however, an
electromagnetic shield is not fully formed for the insulating
substrate 105 and the control substrate 113. Therefore, there has
been a problem in that the power module is easily influenced by
external noises made by a driving motor or the like and reliability
is deteriorated.
Moreover, the base plate 102 and the heat sink 101 are fixed to
each other with the bolt 103. For this reason, it is necessary to
provide a space for forming a bolt hole for the bolt 103 in an
upper surface of the heat sink 101. Consequently, there has been a
problem in that the size of the heat sink 101 is increased.
Furthermore, a warp is easily generated on the insulating case 107
and the base plate 102 by heating for thermosetting the silicone
gel 112 and heating for bonding the insulating substrate 105 to the
base plate 102. Consequently, the thickness of the thermal
conduction grease 116 cannot be reduced so that a thermal
resistance is increased and heat-radiation effects produced by the
heat sink 101 are reduced.
SUMMARY OF THE INVENTION
In order to solve the problems, it is an object of the present
invention to obtain a power module which is mainly excellent in
electromagnetic shielding effects, is rarely influenced by external
noises and acts as an external noise source with difficulty.
A first aspect of the present invention is directed to a power
module comprising an insulating substrate having a main surface on
which a power semiconductor device is mounted, a control substrate
on which a control IC for controlling the power semiconductor
device is mounted, a conductive support plate to which the
insulating substrate and the control substrate are fixed, and a
conductive case fixed to a peripheral portion of the support plate
for surrounding the insulating substrate and the control substrate
together with the support plate.
A second aspect of the present invention is directed to the power
module according to the first aspect of the present invention,
further comprising a heat sink provided in the case and kept in
contact with a back face of the insulating substrate which is
opposite to the main surface, the support plate including a
refrigerant inlet-outlet coupled to the heat sink, an electrode
electrically connected to the power semiconductor device, and a
control connector electrically connected to the control IC, all of
them being provided through the support plate.
A third aspect of the present invention is directed to the power
module according to the second aspect of the present invention,
wherein the power semiconductor device is a voltage-source
inverter, the power module further comprising a DC capacitor
provided in contact with the heat sink opposite to the insulating
substrate in the case.
A fourth aspect of the present invention is directed to the power
module according to any of the first to third aspects of the
present invention, further comprising a shield plate provided
between the insulating substrate and the control substrate in the
case.
A fifth aspect of the present invention is directed to the power
module according to any of the first to fourth aspects of the
present invention, wherein the case and the support plate are
bonded to each other with sealing property kept therein.
A sixth aspect of the present invention is directed to the power
module according to the fifth aspect of the present invention,
wherein an internal space constituted by the case and the support
plate is filled with an inactive material having insulating
property.
A seventh aspect of the present invention is directed to the power
module according to the sixth aspect of the present invention,
wherein the material functions as a refrigerant, the power module
further comprising a fan provided in the case for circulating the
material in the case.
According to the first aspect of the present invention, both the
insulating substrate and the control substrate are surrounded by
the conductive case and the support plate. Therefore, it is
possible to obtain a power module which is excellent in
electromagnetic shielding effects, is rarely influenced by external
noises and acts as an external noise source with difficulty.
According to the second aspect of the present invention, the
refrigerant inlet outlet, the electrode and the control connector
are collectively formed on the support plate. Consequently, the
structure of the case can be simplified.
According to the third aspect of the present invention, it is
possible to relieve the influence of external noises on the DC
capacitor. In addition, the DC capacitor is provided in contact
with the heat sink. Therefore, heat generated from the DC capacitor
can be absorbed properly through the heat sink.
According to the fourth aspect of the present invention, it is
possible to obtain electromagnetic shielding effects between the
power semiconductor device and the control substrate.
According to the fifth aspect of the present invention, it is
possible to obtain a power module which is excellent in dustproof
property and waterproof property.
According to the sixth aspect of the present invention, the
reliability of the power module can be enhanced.
According to the seventh aspect of the present invention, it is
possible to wholly cool the inside of the case with the circulated
refrigerant, resulting in an enhancement in heat-radiation
effects.
These and other objects, features, aspects and advantages of the
present invention will become more apparent from the following
detailed description of the present invention when taken in
conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view showing a structure of a power module
according to an embodiment of the present invention;
FIG. 2 is a sectional view showing the structure of the power
module according to the embodiment of the present invention;
FIG. 3 is a sectional view showing a structure of a power module
according to a first variant of the embodiment of the present
invention;
FIG. 4 is a sectional view showing a structure of a power module
according to a second variant of the embodiment of the present
invention;
FIG. 5 is a perspective view showing a structure of a conventional
power module; and
FIG. 6 is a sectional view showing the structure of the
conventional power module.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIGS. 1 and 2 are perspective and sectional views showing a
structure of a power module according to an embodiment of the
present invention. For convenience of description and simplicity of
the drawings, the sectional view of FIG. 2 does not always
correspond to a section of the structure shown in the perspective
view of FIG. 1. Referring to FIG. 1, the power module according to
the present embodiment comprises two members, that is, a case 1 and
a support plate 2 in appearance. Referring to FIG. 2, a power
semiconductor device 7 such as a voltage-source inverter is mounted
on a top surface of an insulating substrate 5 through a solder 6. A
main circuit which is not shown is formed on the top surface of the
insulating substrate 5. The main circuit is electrically connected
to the power semiconductor device 7 through a metal wire 8 and
includes a switching circuit and the like. The insulating substrate
5 is bonded through a solder 4 to a top surface of a heat sink 3
fixed to the support plate 2. A DC capacitor 16 having a pair of P
and N electrodes (not shown) is fixed to a bottom face of the heat
sink 3 by adhesion. The DC capacitor 16 serves to prevent a voltage
fluctuation in a power module for large power. The P and N
electrodes of the DC capacitor 16 are connected to an external
power source, a battery or the like through a DC side electrode and
refrigerant inlet-outlet 9.
A control substrate 11 is fixed to the support plate 2. A control
IC 13 for controlling the power semiconductor device 7 is mounted
on a top surface of the control substrate 11 through a solder 12.
Moreover, a circuit pattern which is not shown is formed on the top
surface of the control substrate 11. The circuit pattern is
electrically connected to the control IC 13. The control substrate
11 is electrically connected to the power semiconductor device 7
through a metal wire 21.
The support plate 2 is provided with a plurality of (three in FIGS.
1 and 2) electrodes 10, the DC side electrode and refrigerant
inlet-outlet 9, and a control connector 15. The electrode 10 is
electrically connected through the metal wire 8 to the main circuit
formed on the top surface of the insulating substrate 5. The DC
side electrode and refrigerant inlet-outlet 9 is coupled to the
heat sink 3. The control connector 15 is electrically connected
through a metal wire 14 to the circuit pattern formed on the top
surface of the control substrate 11. More specifically, the control
connector 15 is electrically connected indirectly to the control IC
13. The control connector 15 serves to transmit and receive a
control signal between an internal circuit and an external circuit.
All of the electrode 10, the DC side electrode and refrigerant
inlet-outlet 9 and the control connector 15 are formed through the
support plate 2, and are fixed to the support plate 2 by adhesion,
for example. In this case, the use of a room temperature setting
adhesive can prevent a warp from being generated on the support
plate 2.
The case 1 is fixed to a peripheral portion of the support plate 2,
and surrounds the insulating substrate 5, the control substrate 11,
the heat sink 3 and the DC capacitor 16 together with the support
plate 2. More specifically, the insulating substrate 5, the control
substrate 11, the heat sink 3 and the DC capacitor 16 are provided
in an internal space constituted by the case 1 and the support
plate 2. The case 1 and the support plate 2 are bonded to each
other through seam welding, adhesion or the like, for example.
Consequently, it is possible to maintain sealing property of the
internal space constituted by the case 1 and the support plate 2
and to obtain a power module which is excellent in
environment-proof property such as dustproof property, waterproof
property or the like. In the case in which the bonding is to be
carried out by adhesion, it is desirable that a conductive adhesive
should be used. Thus, electromagnetic shielding effects can be
enhanced.
In order to have conducting property, the case 1 is formed of a
metal having corrosion resistance property, stainless, a metal
having a surface coated with a metallic thin film having corrosion
resistance property by plating or the like, a resin, ceramic or
plastic. For example, the case 1 is formed by the deep drawing of
aluminum. The case 1 is not always constituted as a housing but may
be constituted as a laminated film in which a plastic thin film is
formed on a metal foil. With such a structure, it is possible to
easily perform a manufacturing process and to reduce a
manufacturing cost.
The support plate 2 causes the peripheries of the electrode 10 and
the DC side electrode and refrigerant inlet-outlet 9 to have
insulating property and is formed of a metal. Alternatively, a
conductive layer such as a metal foil may be stuck to a surface of
an insulating substrate except the peripheries of the electrode 10
and the DC side electrode and refrigerant inlet-outlet 9.
Consequently, it is possible to prevent each electrode from being
short-circuited and to make the support plate 2 have conducting
property.
Moreover, the internal space constituted by the case 1 and the
support plate 2 may be filled with an inactive material having
insulating property, for example, pure water, oil, a silicone gel,
SF.sub.6, a flon gas, carbon dioxide, an ammonia gas or the like.
If the internal space is sealed with an epoxy resin, for example, a
warp is generated on the case 1 in a thermosetting process.
However, in the case in which the internal space is filled with oil
or a gel, such a problem does not arise.
According to the power module of the present embodiment, thus, both
the insulating substrate 5 and the control substrate 11 are
surrounded by the conductive case 1 and the support plate 2.
Accordingly, it is possible to obtain a power module which is
excellent in electromagnetic shielding effects, is rarely
influenced by external noises and acts as an external noise source
with difficulty.
The insulating substrate 5 is bonded to the top surface of the heat
sink 3 through the solder 4 or the like, and a bolt is not used
differently from a conventional example. Therefore, it is not
necessary to form a bolt hole on the heat sink 3. Consequently, the
size of the heat sink 3 can also be reduced. In addition, the
conventional base plate can be omitted and the thermal conduction
grease is not required. Thus, a thermal resistance can be reduced,
resulting in an enhancement in heat-radiation effects of the heat
sink 3.
Moreover, the DC capacitor 16 is also provided in the case 1.
Therefore, it is possible to relieve the influence of the external
noises. In the case in which the DC capacitor 16 is provided on the
outside of the case 1, an inductance component of the main circuit
is increased but the above-mentioned problem does not arise. In
addition, the DC capacitor 16 is provided in contact with the heat
sink 3. Therefore, heat generated from the DC capacitor 16 can be
absorbed properly by the heat sink 3.
FIG. 3 is a sectional view showing a structure of a power module
according to a first variant of the embodiment of the present
invention. The heat sink 3 is omitted from the power module shown
in FIG. 2 and a fan 18 is provided in a case 1. A DC capacitor 16
is not shown but is fixed to a support plate 2 in the case 1. A
refrigerant supplied from a DC side electrode and refrigerant inlet
9a into the case 1 is circulated in the case 1 by means of the fan
18, and is then discharged to the outside through a DC side
electrode and refrigerant outlet 9b. In the same manner as
described above, for example, pure water, oil, SF.sub.6, a flon
gas, carbon dioxide, an ammonia gas or the like can be used for the
refrigerant. Consequently, the inside of the case 1 can be wholly
cooled with the circulated refrigerant so that cooling effects can
be enhanced.
FIG. 4 is a sectional view showing a structure of a power module
according to a second variant of the embodiment of the present
invention. A conducive shield plate 17 is further provided in the
power module shown in FIG. 2. The shield plate 17 is provided
between an insulating substrate 5 and a control substrate 11 in a
case 1. Consequently, it is possible to obtain electromagnetic
shielding effects between a power semiconductor device 7 and the
control substrate 11.
While the invention has been described in detail, the foregoing
description is in all aspects illustrative and not restrictive. It
is understood that numerous other modifications and variations can
be devised without departing from the scope of the invention.
* * * * *